Resource hanging

[Shane Marsh]

I can't remember if I have posted about this before (apologies if I have). I've never been able to work out what is going on but some of the nightly WebPageTest speed tests (not every site) come back where usually one (sometimes two) resources hang causing poor LCP scores/load times. I've never been able to work out why. The size of the site or number of resources needed doesn't seem to matter. The top site for example is very small. 

These are some from last night:

https://www.webpagetest.org/result/210114_Di41_4482705b1406df57454fd4612be3bed5/

https://www.webpagetest.org/result/210114_DiVT_d62315c6c06d1950aa7df4dd928e3834/

https://www.webpagetest.org/result/210114_DiSJ_9039636cfb0a7d0d1cf48271393394ea/

https://www.webpagetest.org/result/210114_Di11_288e51c6ce9217663cb11a7f3e2c2571/

Any ideas?

Thanks in advance :)

Shane

[Longinos]

Hi Shane

I have tested only the 1st site, the Teide one.

1.- You have some js inlined at the top, some of it depend on jquery, but jquery is loaded after the snipet, so maybe these snipets don´t run until jquery is loaded.

Maybe you must load jquery at the top of the head section and/or put the snipet at the botoom of the page or allmost at the bottom of the head section when all the css and js files in the head are loaded.

2.- The image for LCP is a css background, so don´t display until the css are loaded and procesed. Need you the parallax efect?

3.- Maybe the cloudfront make some strange header manipulation: webp images have a content-type for jpg, cache-control is set to private, don´t have etag header, images are gziped....

4.- The page weigth is 2,6Mb (compresed) and the images are 2,1Mb, make it more ligth. The  l and r side images are near to 1mb.

Try this image and see how it look. Is 50% less kb.

[Shane Marsh]

OMG! Thanks for this. You have many ideas I hadn't considered including seeing if this issue is related to page weight. There are some checks I can put in place to test for that because the issue affects a number of sites beyond the list I gave. Also thanks for spotting the content type issue - that's a strange one. I will look into it. 

I'll come back to you when I've done some more digging - likely to be next week. 

Many thanks

Shane

[Shane Marsh]

Still looking into your previous message but I noticed  this result this morning. 

https://www.webpagetest.org/result/210118_DiTX_722e0651eb71936bc9ebd4d5f0d7817a/1/details/#waterfall_view_step1

Can't make sense of this. Why would 1 resource hang like that?

Kind regards, 
Shane

[Shane Marsh]

I'm now thinking this might not be an issue for you guys. I'm seeing the problem arise with files that have not been optimised. Although I can't rule out pagespeed mod, I am looking through the rest of the stack tweaking the filesystems nginx buffers and load balancers to see if there are issues elsewhere.

Thank you so much for your help!

Shane